Permanent magnet materials are one of the very important electrical and electronic materials which are used in an extensive range covering from various electrical appliances for domestic use to the peripheral devices of large-scaled computers. With recent demands for electrical and electronic devices to reduce in size and increase in efficiency, it has increasingly been desired to improve the efficiency of the permanent magnet materials, correspondingly.
Typical permanent magnet materials currently in use are alnico, hard ferrite and rare earth-cobalt magnets. Recent uncertainty of supply of the raw material for cobalt has caused decreasing demand for the alnico magnets containing 20-30% by weight of cobalt. Instead, rather inexpensive hard ferrite is now taking that position for magnet materials. On the other hand, the rare earth-cobalt magnets are very expensive, since they contain as high as 50-65% by weight of cobalt and, in addition thereto, Sm that does not abundantly occur in rare earth ores. However, such magnets are mainly used for small magnetic circuits of high added value due to their much higher magnetic properties over those of other magnets. In order that the rare earth magnets are employed at low price as well as in wider ranges and amounts, it is required that they be freed of expensive cobalt or they contain only a reduced amount of cobalt, and their main rare earth metal components be light rare earth which abounds with ores. There have been attempts to obtain such permanent magnets. For instance, A. E. Clark found out that sputtered amorphous TbFe.sub.2 had an energy product of 29.5 MGOe at 4.2.degree. K., and showed a coercive force iHc of 3.4 kOe and a maximum energy product (BH)max of 7 MGOe at room temperature upon heat-treated at 300.degree.-500.degree. C. Similar studies were made of SmFe.sub.2, and it was reported that an energy product of as high as 9.2 MGOe was reached at 77.degree. K. However, these materials are all thin films prepared by sputtering, from which any practical magnets are not obtained whatsoever. It was also reported that the ribbons prepared by melt-quenching of PrFe base alloys showed a coercive force iHc of 2.8 kOe. Furthermore, Koon et al found out that, with melt-quenched amorphous ribbons of (FeB).sub.0.9 Tb.sub.0.05 La.sub.0.05, the coercive force iHc reached as high as 9 kOe upon annealed at 627.degree. C., and the residual magnetic flux density Br was 5 kG. However, the (BH)max of the obtained ribbons is then low because of the unsatisfactory loop rectangularity of the demagnetization curves thereof (N. C. Koon et al, Appl. Phys. Lett. 39(10), 1981, 840-842 pages). L. Kabacoff et al have reported that a coercive force on the kOe level is attained at room temperature with respect to the FePr binary system ribbons obtained by melt-quenching of (FeB).sub.1-x Pr.sub.x compositions (x=0-0.3 in atomic ratio). However, these melt-quenched ribbons or sputtered thin films are not any practical permanent magnets (bodies) that can be used as such, and it would be impossible to obtain therefrom any practical permanent magnets. It comes to this that it is impossible to obtain bulk permanent magnets of any desired shape and size from the conventional melt-quenched ribbons based on FeBR and the sputtered thin films based on RFe. Due to the unsatisfactory loop rectangularity of the magnetization curves, the FeBR base ribbons heretofore reported are not taken as being any practical permanent magnets comparable to the conventionally available magnets. Since both the sputtered thin films and the melt-quenched ribbons are magnetically isotropic by nature, it is virtually almost impossible to obtain therefrom any magnetically anisotropic permanent magnets of high performance for the practical purposes.